Electric lamp.



O. SCHALLER.

ELECTRIC LAMP.

APPLICATION FILED 1AN.20, I913.

1,155,963. Patented 001;. 5, 1915.

566161519: [kl W210)":

OTTO SCHALLER, OF S'E DENDE, NEAR BERLIN, GERMANY.

ELECTRIC LAMP.

Specification of Letters Patent.

Patented Oct. 5, 1915.

Application filed January 20, 1913. Serial No. 743,151.

To all whom it may concern:

Be it known that I, O'r'ro SGHALLER, a citizen of the German Empire, and residing at Siidende, near Berlin, German Empire, have invented certain new and useful Improvements in Electric Lamps, of which the following is a full, clear, and exact description.

It is known in connection with electric lamps to provide the current feeds with laterally extending ointing surfaces which are held tightly together by means of the atmospheric pressure. In this connection, however, the current conductors and their joints have always been arranged so that the atmospheric pressure exercised on the contacting surfaces of the joint was always practically at right angles to the surfaces of the joint.

It has now been found that a different embodiment of the invention is of particular advantage. In this embodiment of the invention the vertical axes of the joint surfaces either coincide or converge. Thus, the lines or directions of pressure are either diametrically opposite or converge toward each other. This enables a reduction in the cost of production, an improvement in the oint and simplicity in the construction of the lamp.

In order to render the present specification easily intelligible reference is had to the accompanying drawings in which slmilar letters of reference denote similar parts throughout the several views.

Figure 1 is a vertical section through one form of embodying the invention. Fig. 2 is a similar form of a modification of the invention. Figs. 3 and 4 are vertical section and plan respectively of further modification. Fig. 5 shows a part sectional elevation of a further modification of the joint. Figs. 6 and 7 show sectional views respectively of a straight and curved tubular lamp.

Referring first to Fig. 1, to the top of the open globe or bulb a of the lamp a ring 7 of conductive material is attached by means of a packing ring (1 and on this ring is mounted a dome or similarly constructed part 9 of conductive material, a packing ring d of insulating material being inserted between the two parts. The current conducting parts f and g carry the jointing surfaces for the lamp and form laterally projecting parts of the current feed 0 for the filament b. The current feeds or terminals 0 may be rigidly or detachably connected to the parts f and 9 serving as packing rings.

F g. 2 shows the same construction in connectlon with a practically cylindrical form of lamp; 1n which the dome g is replaced by a substantially flat cover 9', while the conductive ring f has a rectangular cross section, instead of the H-form of Fig. 1. By these examples it is intended to show that the lnvention can be carried out in many ways as regards the two joints irrespective of the form of the lamp, of the surfaces of the joints and of that of the current conductors connected with the terminals 0.

Referring now to Figs. 3 and 4, they show two different forms of the'invention. In this case, the globe or bulb consists of two hemispheres or partial spheres a and a and these two parts may be of different sizes. The rim of the upper part a closes on to the conductive ring 9 and that of the lower half or part, against the conductive ring f. Both rings are closed together by means'of the packing ring (Z of glass or other nonconducting substance. The current feeds 0 are connected up to the rings 9 and f and to one or more filaments I). These filaments may be connected up singly or in groups to each other in parallel or in series. The joint shown in Fig. 3 differs from that in Fig. 4 in that the conductive rings f and 9 have an H-shaped cross-section to receive the packing rings h, the material of which may be conductive or non-conductive, while with the construction shown in Fig. 4 the packing rings themselves serve simultaneously as current conductors. In this case, the filaments Z) are arranged radially the current feed being efiected on the one hand by means of the bridge 0 connected with g to the central connecting piece 6, and on the other hand by the ring f to the ends of the filaments connected therewith. The upper dome or hemisphere may take the form of a reflector.

The parallel arrangement of the filaments has the advantage that the breakage of a filament will not render the lamp useless.

' The packing must be very carefully at tended to and may consist of any suitable substances, particularly those disclosed in my patent hereinbefore referred to.

The arrangen'ient of the joints or packing referred to and described in connection with Figs. 1-4 enables an external or additional joint to be employed forming a common seal for both joints, as illustrated diagrammatically in Fig. 5. To the lower part a of the lamp a glass ring or annular trough r is attached in suitable manner so as to produce an annular gutter around the globe or bulb which extends over the joints of the current conducting parts f and g with the lamp parts a and a as also over the insulating ring d and which is filled with 011 or some other insulating and sealing liquid; As a packing material between metal and glass, india rubber, impregnated paper and other packing materials, have proved to be quite adequate as far as air-tightness is concerned, but the bulb or globe gradually becomes heated without however oxidizing the filament. From this fact it would appear that although no air enters from the outside,

ases free of oxygen are generated inside the amp and that the reason is to be found in the fact that gas is given off by the packing material. It is therefore advantageous to employ packing materials which do not give off gases. If a metal is employed, for 1nstance lead, it is necessary to obtain a perfectly tight joint, to employ a temporary pressure, at which the packing material begins to melt, so that even the smallest unevennesses of the surfaces to be joined will be filled out. This condition cannot be fulfilled with certainty in every case by tightly screwing up the parts, because in the first place the pressure exerted in screwing the parts together is not always even at every joint and secondly because alterations of temperature affect the parts screwed to-- gether and the packing material to a different degree.

With the present arrangement of the packing and with the dimensions of high candle power lamps, it is rendered possible that the surfaces to be joined, receive a pressure of several kilos per sq. cm. and if this pressure is not suflicient to melt or'liquefy the packing material, it can be increased in a compressor to the necessary extent. Thus, for instance a spherical bulb or globe of 30 cm. external diameter having annular packing surfaces of 3 mm. breadth on being evacuated would have a pressure of 25 kilos per sq. cm. at its largest diameter, so that it would be quite sufiicient to subject the same to a temporary excess of pressure of one or a few atmospheres, in a compressor, to attain a liqii efying or melting of the lead packing. he packing may also be heated in order to soften the material, or to render less the necessary pressure.

The conductors, which are to be jointed to the non-conducting substances may also consist of metal or any other suitable material and they may also be provided with a metal coating, such as lead, gold, or the like or be covered with metal foil. Metal packing of this description is well able to withstand variations of temperature, they follow the different degrees of expansion of the materials of the lamp, without losing any of their packing properties.

In connection with all of the above described embodiments of the present invention the packing surfaces have a common axis. It is however not necessary that these packing surfaces lie close together, they may, for instance, be at opposite ends of the lamp, as represented diagrammatically in the tubular lamp a of Fig. 6. In this case the joint itself is not illustrated. The covers g and f ma also be made of conducting material which also forms the packing medium. The direction of pressure is indicated by the arrows. In Fig. 7 a lamp is illustrated in which the axes of the packing surfaces and with them the lines of pressure converge, as shown by the arrows the tubular lam a being curved and diagrammatically il ustrated, without showing the particular methodof acking. In both Figs. 6

-- and 7 the termina s c are connected up by the filaments b.

It is self-evident that the invention could be embodied in many other forms. The method of'connection of the filaments or the like with the conductors, is immaterial as far as the present invention is concerned.

I claim as my invention 1. In an incandescent electric lamp a globe having an open ended part, on which a transversely disposed bearing surface is formed around the opening for the feed conductors, an annular conducting member seated with packing and insulating means on said bearing surface and serving for the feed connection on the one end of the filament, the globe beingclosed by a cover serving as a carrier for the feed connection of the other end of the filament and which cover fits over the annular conducting member and presses it together with the packing and insulating means onto the transversely disposed bearing surface, said parts being held together by atmospheric pressure.

2. In an incandescent electric-lamp a globe having open ended parts extendin in opposite directions, each provided wit a transversely disposed surface and'surrounding an opening for a single feed conductor, a cover serving as'a carrier for the feed connection of the end of the filament and adapted to be pressed tightly onto the said transversely disposed surface by atmospheric pressure.

3. In an incandescent electric-lamp a globe having an openended part, provided with a transversely disposed surface, a cover closed by atmospheric pressure over this seat and onto an interposed insulated ring the combination of a filament having one end attached to the insulated ring and the other to the cover, a ring surrounding the joint to contain a liquid.

In testimony whereof I afiix my signature in the presence of two Witnesses.

OTTO SOHALLER.

Witnesses:

VOLDEMAR HAUPT, HARRY L. WILSON. 

